The rapid growth of chiral pharmaceutical industry benefits largely from the great development of asymmetric synthesis methodology which, in reverse, is facilitated by chiral pharmaceutical industry as well. Asymmetric catalytic organic synthesis is one of the most efficient and favorable ways to obtain chiral compounds. In asymmetric catalytic organic synthesis, the key point to achieve high reactivity and enantioselectivity is the structure of chiral phosphine ligands. Therefore, development of chiral phosphine ligands is always a research focus in both academic and industrial field.
In 1996, ZHANG Wanbin and IKEDA Isao et al. synthesized for the first time a C2-symmetrical ferrocene-P,P-ligand having only planar chirality, and used it successfully in an allylic substitution reaction, achieving an optical yield as high as 94% e.e.
Just as in C2-symmetrical axial chiral ligands, in the asymmetric catalytic reaction, the degree of the dihedral angle created by ligation between chiral ligands and metals tends to be the key factor influencing the asymmetric induction in a catalytic reaction. A slight change in such an angle could impact the stereoselectivity of the asymmetric catalytic reaction considerably. It could be expected that, for the ferrocene-based ligands, the distance between the two cyclopentadiene rings could be adjusted by changing the metallocene. Consequently, the dihedral angle (torsional angle) formed during ligation between the ligand and the metal would be changed, and eventually the chiral field in the asymmetric catalytic reaction could be changed. Following this idea, in the present invention, a novel C2-symmetrical ruthenocene diphosphine ligand having only planar chirality is designed and synthesized so as to screen for novel universal catalysts with high catalytic activity and enantioselectivity by investigating the influence of the dihedral angle in planar chirality on the asymmetric catalytic effectiveness.
Through a literature research in the prior art, no subject matter same or similar as that of the present invention is found up to now.